1. Technical Field
The present invention relates to the testing of nozzles.
2. Related Art
Ink jet printers perform printing by discharging ink inside cavities. The ink thickens when drying. When the ink inside the cavities thickens, discharging failure may be caused. Therefore, it is preferable to test whether the ink has thickened. As such a test, a method is known where vibration is applied to the ink inside the cavities to determine the degree of viscosity based on the behavior of the ink with regard to the vibration. This vibration is known as residual vibration. The method is superior in terms of being able to be carried out without interrupting printing (for example, Japanese Patent No. 4114638).